What Are Smile Lines and Why Do They Get Deeper Over Time?

Smile lines, also known as nasolabial folds, are the creases that run from the sides of your nose down to the corners of your mouth. Everyone has them to some degree. They show up when you smile, laugh, or make facial expressions. But over time, for a lot of people, these lines become deeper, more visible, and eventually stick around even when the face is completely at rest.

Why Does Everyone Have Them?

Nasolabial folds are a normal part of facial anatomy. They exist because of the natural boundary between the cheek and the upper lip area. When you smile, the cheek tissue pushes against this boundary and creates a fold. In younger faces, the fold disappears as soon as the expression relaxes because the skin has enough elasticity and the underlying tissue has enough volume to bounce back.

Why Do They Get Deeper with Age?

Several things happen as you age that cause these lines to deepen and become more permanent.

The fat pads in the cheeks shrink and descend. The midface has natural fat compartments that provide fullness and support. As these fat pads reduce in volume and shift downward with gravity, the cheek tissue drops, and the fold between the cheek and the lip becomes deeper. This is often the biggest driver of deepening nasolabial folds.

Collagen and elastin decline. As the skin produces less of these structural proteins, it becomes thinner, less firm, and less able to snap back into place after repeated expressions. Lines that once only appeared during a smile start to etch themselves into the skin permanently.

Bone resorption in the midface and jaw reduces the underlying support structure. As the cheekbones lose projection, there's less scaffolding to hold the soft tissue up, which allows it to sag and fold.

Repeated facial expressions play a role too. Every smile creates that fold. Over decades, the constant repetition contributes to a permanent crease forming in the skin.

Are They Just a Cosmetic Concern?

Yes. Nasolabial folds don't cause any pain or health problems. But for many people, deep smile lines can make the face look tired, sad, or older than they feel. It's one of the most common reasons people seek cosmetic treatment for the mid and lower face.

What Can Be Done About Them?

If the primary cause is volume loss in the cheeks, restoring volume to the midface can lift the tissue and soften the fold from above. This is often the most effective approach because it addresses the root cause rather than just filling the line itself.

If the fold is primarily a deep crease in the skin, product can be placed directly into or alongside the fold to smooth it out. This is a more targeted approach and works well for moderate to deep lines.

In many cases, a combination of both, restoring cheek volume and softening the fold directly, produces the most natural-looking result.

Results are visible immediately and typically last between 12 and 24 months depending on the area treated and the product used.

The Important Thing to Understand

Nasolabial folds can't be eliminated completely. They're a natural part of facial structure, and even the best treatment won't make them disappear entirely. The goal is to soften them, restore balance, and make the face look more refreshed and proportionate.

A consultation with a qualified practitioner is the best way to understand what's causing your smile lines and which approach would give you the most natural result.

This content is intended for educational purposes and does not constitute medical advice or a recommendation for treatment. Only licensed healthcare providers should perform injectable procedures.